SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'da0c848e194734a7aee3fcf5da78b6da469718c8dc286a770f5d8957b273e11b' 
  AND token = 'SLZag/4v4GOsazAwKLHjovjgNgGR4Z1DaAoVsJukm/8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}